Means for controlling the charge and discharge of a storage battery



Feb.4, 1936. E. L. I @RD 2,029,628

MEANS FOR CONTROLLING THE CHARGE AND DISCHARGE OF STORAGE BATTERY FiledMarch 28, 19152 Cuba/uam Shu-45AM frown/5y.

Patented Feb. 4, 1936 UNITED STATES PATENT OFFICE wam MEANS AND 'miurFOB CONTBOLLING THE CHARGE DISCHARGE 0F A STORAGE BAT- Edward L. Lord,Glenside, Pa., asslgnor to The Electric Storage Battery Company,Philadel- Phia, Pa., a corporation of Pennsylvania Appunti@ mmh 2s,1932, semi No. 601,600v s claims. (c1. 111-314) the variations in loadso that the greater part of these variations will be carried by thesource and will not fall onv the battery, the battery being suppliedwith a small amount of charging current suillcient to compensate forinternal losses so long as the supply of 'current from the source isavailable, and the battery to be subject to discharge only when thesupply vof current from the source is interrupted.

In carrying out my invention, I provide `a transformer between the A. C.source and the rectifier, this transformer being designed with an ironcore having a magnetic shunt arranged to divert a portion of themagnetic ilux developed in the primary winding so that only a portionVol! the total ux passes through the secondary Winding.` An encitingcoil in series with the load is arranged on the magnetic shunt toproduce a degree of saturation in this shunt varying with the load, thusvarying the reluctance of the magnetic shunt path and thereby varyingthe amount of flux divertedirom-the secondary'winding.

The invention will be more clearly understood by reference tothefollowing description taken in conjunction with vthe accompanyingdrawing, which description and drawing illustrate one form my inventionmay take.

the transformer T, whose primary winding I5 is connected tothe A. C.circuit I6, I1, while the other two junctions of the Wheatstone bridge5, 8 are connected to the terminals of the storage battery 1. Thebattery is connected to the D. C.

load circuit by conductor 8 on one side and conductors 9 and III on theother side. In series with conductors 9 and III are connected controlcoils 'Il and I2 on transformer T.

Transformer T consists of four magnetic paths I8, I8, 20 and 2|connected in parallel. The two paths 2II and 2| constitute the maintransformer on which are wound the primary winding I5 and the secondarywinding 22 respectively. The other two paths I8 and I9 constitutemagnetic shunts to the main paths 20 and 2|, The magnetic ilux in pathzn'wu be that required to devemp in the winding I5 the necessary counterE. M. F. substantially to balance the applied E. M. F. In the absence ofthe shunt paths I8, I9, this entire ilux would pass through the path 2|,developing a corresponding voltage in the secondary winding 22, itsvalue depending on the ratio of turns in the two windings. The iluxshunted through paths'l8 and I 8 will reduce by a corresponding amountthe flux passing through 2| and will, therefore, reduce the secondaryvoltage. The ilux shunted through I8 and I8 will depend upon themagnetic reluctance of these paths and will Vbe a maximum when thesepaths are unsaturated.

. in secondary voltage will increase the direct current delivered to thebattery terminals through the rectier. I. By properly designing-.theapparatus, the direct current delivered to the battery terminals can bemade to increase or decrease by amounts corresponding to the increase ordecrease in the load. Variations in load will thus fall on the source ofA. C. current, and

` the battery 'will`be relieved of these variations and will iioatacrossy the circuit, receiving only the necessary charging current forcompensating for internal loes. Y

It will be noted that the coils II and I2 are so wound as to cause alocalized magnetic ilux to pass through the magnetic paths I8 and I8 asa closed magnetic circuit. Also,the direction vin which these two coilsII and I2 are wound is such that the, alternating flux shunted throughthem from the core 28v 0f the primary winding I5 will develop equal andopposite alternating voltages in the coils I I .and I2 which willneutralize each other and thus prevent the eiiect of the shuntedalternating ux from being felt in the D. C. load circuit.

- In order to adjust the voltage applied to the battery when there is noload on the D. C. circuit, I provide manual means for varying the reluc-Atance of the magnetic shunt here shown as an air gap A23, whosereluctance is varied by inserting manually to a greater or less extent ablock of magnetic material 2l. Other well known means l5 for varying thevoltage applied to the rectifier by the secondary winding may of coursebe used. I do not intend to be limited in the practiceof my inventionsave as the scope of the prior art and of the attached claims mayrequire.

t Iclaim: i

1. In combination, an A. C. supply circuit, a

transformer having four parallel paths Vfor magnetic flux, a primarywinding connected to the A. C. circuit on one of said paths, a secondarywinding on another of said paths, a rectifier connected to the secondarywinding, a storage battery connected to receive unidirectional currentfrom the rectiiier, a D. C. load circuit connected to the battery, andtwo coils in series in the D. C. load vwinding, a secondary winding onsaid core detached from said primary winding but adapted to receiveinduced current therefrom, a rectifier connected to said secondaryWinding, a battery connected to said rectifier to receive unidirectionalcurrent therefrom, a D. C. load circuit connected to said battery, andmeans connected in series with said D. C. circuit and said batteryresponsive tothe load on said circuit and wound on said core for varyingthe magnetic iiux passing from said primary Winding to said secondarywinding to thereby vary the amount of current fed by said secondarywinding to said rectifier.

-3. A combination according to claim 2 having means for adjusting thecore for shunting from the secondary winding a part of the magnetic iiuxpassing through the 'primary 4. 'In combination, an A. C. supplycircuit, a transformer havinga magnetic core and having a primaryconnected to said supply circuit embracing one portion of said core andhaving a secondary winding disconnected from said pri- -mary windingembracing another portion of said core, a rectier connectedto saidVsecondary Winding, a D. C. circuit connected to said rectifier, meansfor shunting from the secondary winding a part of the magnetic fiuxpassing through the primary winding, and means connected across saidbattery in series with the load on the D. C.

circuit and responsive to the load on the D. C.A

circuit for varying the shunting effect of said .shunting means withoutaecting the reluctance of the magnetic circuit embraced by the primaryand secondary ,windings 5. In combination, an A. C. supply circuit, a

transformer having a magnetic core and having a primarywinding-connected to said supply circuit embracing one portion of saidcore and having a secondary winding disconnected from said primarywinding embracing another portion of said core, a rectifier connected tosaid secondary winding, a D. C. circuit connected to said rectifier,

. means for shunting from vthe secondary Winding4 a part of the magneticiiux passing through the primarywinding, means connected across saidbatteryin series with the load on the D. C. circuit and responsive tothe load on .the D. C. circuit for varying the shunting eifect of said`shunting means withoutV aiecting the reluctance of the magnetic circuitembraced bythe primary and secondary windings, and other meansindependent of the load on the D. C. circuit for varying the shuntingeffect of said shunting means.

6. In combination, an A. C. supply circuit, a

transformer, a primary winding on said transformer connected to the A.C. circuit, a secondary IWinding of the transformer detached from saidprimary winding but adapted to receive induced current therefrom, arectier connected to said secondary a storage battery connected toreceive unidirectional current from said rectier, a D. C. load circuitconnected to said battery, means for shunting from the secondary windinga part of the magnetic flux passing through the primary winding, andmeans connected across said battery in series with the load on the D. C.circuit and responsive to the load on the D. C. circuit 'for varying theshunting eiect of said shunting means without aifecting the reluctanceof the magnetic circuit embraced by the primary and secondary windings.-

7. InV combination, a variable load, a storage battery connected withsaid load', a transformer havingaprimaryandasecondary,aux'path forby-passing a portion of the flux of said transformer from saidsecondary, a rectifier having its input terminals connected with saidsecondary and its output terminals connected with -said battery, andmeans effective when said loadis increased .for increasing thereluctance of said Vpath to. increase the charging current ilowing intosaid battery.

8. I n combination, a variable load, a storage battery connected withsaid load, a reactive transformer having a primary and a secondary, arectiiler having its input terminals connected with said secondary andits output terminals connected with said battery, and means connectedacross said battery in series with said load and eiective,

when said load is increased for decreasing 'the leakage reactance ofsaid transformer to increase EDWARD L. LORD.

the charging current ilowing into said battery.

